Iranian meddling in neighboring Afghanistan raises new concerns about an old troublemaker

But since the fall, the U.S.-Iran warming trend has abated. Iranian officials grumble that they have received precisely nothing for their good behavior during the war and its aftermath. Iran has committed more money ($560 million over five years) than any other country to the international aid package for Afghanistan. (The U.S. has pledged $297 million for Afghanistan in the next year.) Western diplomats praise Iran for helping broker the Bonn agreement that created Afghanistan's provisional government. But that's not enough to pull Iran out of the terror-state doghouse or persuade the U.S. to lift economic sanctions against the regime.

Suspicion about Iran's current agenda in Afghanistan will not help. It's no secret that both Iran's reformist government and its religious establishment want to nurture a Tehran-friendly government in Kabul and prevent the U.S. from gaining a foothold in Iran's backyard. Its ruling clerics distrust interim Afghan President Hamid Karzai because of his long-standing loyalty to exiled King Mohammed Zahir Shah. A Western diplomat told TIME that Iranian officials in Afghanistan began attempting to influence the shape of the future government late last year by providing their preferred candidate, former President Burhanuddin Rabbani, with hundreds of thousands of dollars in cash so he could buy the loyalty of tribal elders in eastern Afghanistan.

It didn't work, but Tehran has kept at the intrigue. Foreign diplomats in Kabul told TIME that in a meeting this month with Afghanistan's interim Defense Minister, Mohammed Fahim, Iranian intelligence agents encouraged Fahim to resign from the new government and take his forces with him--a move, the diplomats say, that was intended to topple Karzai's government and spoil U.N. plans to hold a grand tribal assembly in May. The sources say Fahim spurned the Iranians, but that has not stopped Ismail Khan, a Persian-speaking Tajik, from continuing to take their arms and money.

Iran defends its support of Khan and claims it has told him to fall in behind Karzai's government in Kabul. "There's no truth to allegations of supporting a faction," says Deputy Foreign Minister Javad Zarif. "The objective of this exchange is to enhance cooperation, not to provoke rivalry." The Iranian government says it has little interest in fomenting chaos in Afghanistan that would give rise to another Taliban. A Western diplomat in Tehran gives credence to Iran's defense: "There's a more negative spin than is warranted. Right now, Iran's game is to be publicly obstructive and privately constructive."

Not everyone sees it that way. Western intelligence sources told TIME that elements of the Revolutionary Guards have encouraged Hazaras--ethnic minorities in Afghanistan who, like most Iranians, practice Shi'ite Islam--to turn against the U.S. troop presence. "They're not telling the Hazaras to drive the Americans out," says an official. "But we're worried this will be a green light to take action."